A Sommer

Digital Mammography Screening with Photon-counting Technique: Can a High Diagnostic Performance Be Realized at Low Mean Glandular Dose?

PURPOSE To assess screening performance of a direct radiography (DR) photon-counting system versus statewide screening units with different digital technologies. MATERIALS AND METHODS The local ethics board approved retrospective study of prospectively acquired data from the North Rhine-Westphalian mammography screening program (2009-2010). Informed consent was waived. Examinations in 13 312 women with a DR photon-counting system and statewide digital screening examinations in 993 822 women were included (37 computed radiography mammography systems and 55 DR systems). Diagnostic performance was assessed with cancer detection rate, recall rate, and proportion of small invasive cancers and ductal carcinoma in situ (DCIS). Mean glandular dose was calculated for DR photon counting and for a conventional DR subgroup. Differences were tested with χ(2) and t tests (P < .05). RESULTS The cancer detection rate for subsequent screenings was higher for DR photon counting than statewide rates (0.76% [67 of 8842] vs 0.59% [3108 of 527 194], P = .05) at a higher recall rate (5.4% [475 of 8842] vs 3.3% [17 656 of 527 194], P = .001). Detection of invasive cancers up to 10 mm for DR photon counting was high for initial (40% [14 of 35]) and subsequent (42% [19 of 45]) screenings but not significantly different from statewide rates (initial, 31.6% [942 of 2979], P = .50; subsequent, 32.5% [765 of 2353], P = .25). The DCIS subsequent screening rate was higher for DR photon counting than statewide screening (0.23% [20 of 8842] vs 0.12% [616 of 527 194], P = .01) and the conventional DR subgroup (0.23% [20 of 8842] vs 0.12% [65 of 52 813], P = .025). Mean glandular dose for DR photon counting was significantly lower than that for conventional DR (0.60 mGy ± 0.20 vs 1.67 mGy ± 0.47 [craniocaudal views], 0.64 mGy ± 0.23 vs 1.79 mGy ± 0.53 [mediolateral oblique views], both P = .0001). CONCLUSION Digital mammography screening with dose-efficient photon counting enables desirable detection rates of small invasive cancers and DCIS. Higher detection rates compared with statewide performance occurred with subsequent screening but had higher recall rates.

Relationship between Detector Size and the Need for Extra Images and their Effect on Radiation Exposure in Digital Mammography Screening

PURPOSE To determine the number of extra images (EI) that are necessary for imaging large breasts when using a detector smaller than 24 cm × 30 cm and to calculate the additional average glandular dose (AGD) for these images. MATERIALS AND METHODS The screening mammograms taken between 2007 and 2011 were assessed for a photon counting full-field digital mammography (PCM) system (detector size: 24 cm × 26 cm) and a computed radiography (CR) system (24 cm × 30 cm). The number of EI was recorded and the AGD calculated. This AGD was compared with the mean AGD of 47 conventional full-field digital mammography (FFDM) systems. RESULTS A total of 62,466 examinations were analyzed. EI had to be taken in 0.6 % (199/32,766) of all PCM examinations and 0.3 % (90/29 700) of all CR examinations. This corresponded to a total of 327 and 191 EI for the PCM and CR systems, respectively. More than one quarter of the examinations with EI were necessary because the breast was not properly positioned in the original image (PCM 31 %, CR 29 %). The mean AGD per EI was 0.7 ± 0.1 mGy for the PCM and 2.6 ± 1.2 mGy for the CR system. The mean AGD for all breast thicknesses for FFDM was 1.4 ± 0.3 mGy. CONCLUSION In general, large breasts cannot be imaged with just one image per view. The number of examinations where EI are needed is doubled with the 24 cm × 26 cm detector of the PCM system. However, the absolute number is small. The total dose, as the sum of the original and the EI, is equal to the mean AGD of a single image of the FFDM systems and lower than the dose of a single image with the CR system.

Zentrale Online-Qualitätssicherung in der Radiologie: eine IT-Lösung am Beispiel des deutschen Mammografie-Screening-Programms

PURPOSE Physical-technical quality assurance is one of the essential tasks of the National Reference Centers in the German Breast Cancer Screening Program. For this purpose the mammography units are required to transfer the measured values of the constancy tests on a daily basis and all phantom images created for this purpose on a weekly basis to the reference centers. This is a serious logistical challenge. To meet these requirements, we developed an innovative software tool. MATERIALS AND METHODS By the end of 2005, we had already developed web-based software (MammoControl) allowing the transmission of constancy test results via entry forms. For automatic analysis and transmission of the phantom images, we then introduced an extension (MammoControl DIANA). This was based on Java, Java Web Start, the NetBeans Rich Client Platform, the Pixelmed Java DICOM Toolkit and the ImageJ library. RESULTS MammoControl DIANA was designed to run locally in the mammography units. This allows automated on-site image analysis. Both results and compressed images can then be transmitted to the reference center. We developed analysis modules for the daily and monthly consistency tests and additionally for a homogeneity test. CONCLUSION The software we developed facilitates the immediate availability of measurement results, phantom images, and DICOM header data in all reference centers. This allows both targeted guidance and short response time in the case of errors. We achieved a consistent IT-based evaluation with standardized tools for the entire screening program in Germany.

Digital breast tomosynthesis plus synthesised images versus standard full-field digital mammography in population-based screening (TOSYMA): protocol of a randomised controlled trial

Introduction Development of digital breast tomosynthesis (DBT) provides a technology that generates three-dimensional data sets, thus reducing the pitfalls of overlapping breast tissue. Observational studies suggest that the combination of two-dimensional (2D) digital mammography and DBT increases diagnostic accuracy. However, because of duplicate exposure, this comes at the cost of an augmented radiation dose. This undesired adverse impact can be avoided by using synthesised 2D images reconstructed from the DBT data (s2D). We designed a diagnostic superiority trial on a high level of evidence with the aim of providing a comparison of screening efficacy parameters resulting from DBT+s2D versus the current screening standard 2D full-field digital mammography (FFDM) in a multicentre and multivendor setting on the basis of the quality-controlled, population-based, biennial mammography screening programme in Germany. Methods and analysis 80 000 women in the eligible age 50–69 years attending the routine mammography screening programme and willing to participate in the TOSYMA trial will be assigned by 1:1 randomisation to either the intervention arm (DBT+s2D) or the control arm (FFDM) during a 12-month recruitment period in screening units of North Rhine-Westphalia and Lower Saxony. State cancer registries will provide the follow-up of interval cancers. Primary endpoints are the detection rate of invasive breast cancers at screening examination and the cumulative incidence of interval cancers in the 2 years after a negative examination. Secondary endpoints are the detection rate of ductal carcinoma in situ and of tumour size T1, the recall rate for assessment, the positive predictive value of recall and the cumulative 12-month incidence of interval cancers. An adaptive statistical design with one interim analysis provides the option to modify the design. Ethics and dissemination This protocol has been approved by the local medical ethical committee (2016-132-f-S). Results will be submitted to international peer-reviewed journals. Trial registration NCT03377036; Pre-results.

Entwicklung eines Data-Warehouse-Systems zur Evaluation des Mammographie-Screening-Programms

Ziele: In Deutschland wird derzeit ein flachendeckendes und qualitatsgesichertes Mammographie-Screening-Programm aufgebaut. Bundesweit sind funf Referenzzentren unter anderem fur die wissenschaftliche Evaluation dieses Vorsorgeprogramms verantwortlich. Schwerpunkte des Referenzzentrums Mammographie Munster sind neben der Evaluation der Qualitat des Screening-Programms Untersuchungen zur digitalen Mammographie und zur Strahlenexposition. Methode: Zur Erfullung dieser Aufgaben wurde ein Data-Warehouse-System entwickelt welches Daten verschiedener Quellen extrahieren, transformieren und fur die Analyse bereitstellen kann. Die Daten konnen in einer gemeinsamen Basisdatenbank kombiniert und anschliesend durch verschiedene Analysemodule aufbereitet werden. Eine Excel-Schnittstelle ermoglicht Export und Weiterverarbeitung der Daten. Das gesamte System basiert auf Open-Source-Software und wird uber ein Web-Interface gesteuert. Ergebnis: Mit dem Data-Warehouse-System konnten erfolgreich interne und externe Datenquellen importiert und kombiniert werden. Dazu gehoren unter anderem Einladungsdaten der Zentralen Stellen, Evaluations- und Expositionsdaten aus den Datenbanken der Kassenarztlichen Vereinigungen und Daten aus der technischen Qualitatssicherung sowie den Abnahmeprufungen der Mammographiegerate. Verschiedene Module erlauben die gezielte Abfrage und Aufbereitung dieser Daten. So konnten erste Analysen auf Basis von Daten aus Nordrhein-Westfalen durchgefuhrt werden. Schlussfolgerung: Das Data-Warehouse-System ermoglicht, durch seine Automation bei der Verarbeitung der Daten, eine schnelle und einfache Prasentation der fur das Screening-Programm interessanten Parameter. Zusatzlich bildet das System eine Basis fur umfangreichere Analysen. In Zukunft konnten, z.B. durch den Einsatz von Data-Mining-Techniken, Abhangigkeiten und Muster in den Daten ermittelt werden. Diese konnen zur Qualitatssteigerung des Screening-Programms verwendet werden. Korrespondierender Autor: Czwoydzinski J Universitatsklinikum Munster, Referenzzentrum Mammographie, Albert-Schweitzer-Str. 33, 48149 Munster E-Mail: jc@uni-muenster.de